Gabor Szabo

Posted on May 18 • Originally published at perlweekly.com

Perl 🐪 Weekly #773 - The perl-tester Docker image

#perl #news #programming

Originally published at Perl Weekly 773

Hi there!

Recently there were a number of days that the perl-tester Docker image did not build properly. It is always a bit of an issue with it, because there quite a few moving parts. Parts where the dependency isn't fixed. e.g. in most of the cases it installs the most recent version of the modules from CPAN. Which mean any release of any module might break the whole build process. This time, however, the source of the problem was the new release of App::cpm, the tool used to install the CPAN modules. As often the case the new release was intended to improve things: cpm v1: making installs stable, but it broke the build on some of the older versions of Perl just by increasing the minimum version of Perl required.

One solution would be to fix all the dependencies, both tooling and the modules we install, but then someone would need to keep track of changes (the way dependabot does) which is probably way too much work for the few people who contribute to this project. The other solution might be to create an easy way to see what changed between the last successful build and the current failing build. We have started to work on a tool that will help with that. It will also allow us to show exactly what is in every image. BTW If you have spare stars in your pocket, it would be nice if you gave one to the docker-perl-tester project.

A couple of days ago I started to play with FalkorDB, an Open Source Graph Database. I already gave a presentation in Hebrew on how to use in general and specifically in Python. In a couple of hours I am going to give another one - this time in English - an intro to GraphDB. I'll use Rust for the programatic examples. It seems there is no client for it in Perl so it might be an interesting project to build one. The one in Python uses the Redis module for connectivity so I looked at the options to use Redis in Perl. MetaCPAN showed the Redis module as the first hit. Unfortunately that module did not have a commit for 3 years and there are many outstanding Issues and even PRs. So I posted about it both in the Perl Maven WhatsApp group and in the Telegram channel. Within seconds I was pointed towards Mojo::Redis and Redis::XS as alternatives.

Online Events: If you are in an American time-zone then both the Boston Perl Mongers and the Toronto Perl Mongers have semi-regular online meetings in your evening hours with various interesting speakers. If you are in the European time-zones or you don't mind having a meeting in your morning hours in the Americas, then there is the Perl Maven group where it is mostly me giving a presentation or working on some code. For details check out the Perl Weekly events page.

Enjoy your week!

--
Your editor: Gabor Szabo.

Announcements

cpan.org email forwarding has been shut down

The Perl NOC team has shut down the forwarding of email to the cpan addresses. If you are a CPAN author, please make sure MetaCPAN displays ways to contact you. (link to the source git repository of your projects, a LinkedIn account, an email address, etc.)

Articles

cpm v1: making installs stable

I rarely include articles from Medium as most of them are spam, but this one is real. So here you are!

Is your account on blogs.perl.org registered with an @cpan.org email address?

Installing Bit::Vector on Debian 13 (Trixie)

It is good that this information can be found on a public blog post, but IMHO it would be event better if this was part of the README or the documentation of the project.

My Journey with Devel::ptkdb - Origins

Enabling AddressSanitizer (ASan) in Makefile.PL for Linux Environments

Introducing Time::Str

At first I was wondering why this new module when DateTime provides all the features, but then I read on and there are a few reasons. Interesting.

Discussion

Optional stricter normalization of raw ISBN input

An issue that gives an opportunity for you to share your thoughts.

Why does a call to `ref` on a reference to 'substr' produce 'LVALUE'?

Perl

This week in PSC (224) | 2026-05-11

The Weekly Challenge

The Weekly Challenge by Mohammad Sajid Anwar will help you step out of your comfort-zone. You can even win prize money of $50 by participating in the weekly challenge. We pick one champion at the end of the month from among all of the contributors during the month, thanks to the sponsor Marc Perry.

The Weekly Challenge - 374

Welcome to a new week with a couple of fun tasks "Count Vowel" and "Largest Same-digits Number". If you are new to the weekly challenge then why not join us and have fun every week. For more information, please read the FAQ.

RECAP - The Weekly Challenge - 373

Enjoy a quick recap of last week's contributions by Team PWC dealing with the "Equal List" and "List Division" tasks in Perl and Raku. You will find plenty of solutions to keep you busy.

Perl Weekly Challenge 373: Equal List

The clean, logical structure of Abigail's detailed technical analysis provides a very clear and rational basis for how best to apply mathematical theory to practical use. With a focus on optimising the algorithmic complexity rather than executing a brute force approach, Abigail delivers an incredibly efficient solution to this problem that will be valuable to all developers who wish to create highly efficient solutions to their problems.

Perl Weekly Challenge 373: List Division

Abigail's solution to the list partitioning problem is a beautifully crafted and idiomatic implementation that completely avoids the cumbersome index-tracking that traditional loop-based implementations require. The implementation is easy to read and is highly efficient because it leans heavily on the mechanics of the underlying language. This illustrates how an effective structural data transformation paradigm can result in simpler implementations.

List the List

Through a demonstration using gather and take in conjunction with native array splicing Arne demonstrates Raku's capabilities and gives a simple way to distribute remaining list offsets without having to rely on complex nested loops or overhead due to atypical index calculations. The result is a functional representation showing how Raku can eliminate complications associated with the partitioning of structural data, creating an intuitive self-documenting pattern.

Let's Dance to List Division

Bob has produced a superbly developer-oriented analysis addressing the pragmatic aspects of designing APIs using Perl's 'flat' argument list mechanism. Bob's approach to using array references in conjunction with a dual-while-loop, which uses 'destructive splice' calls to divide the input data into well-balanced partitions, enables this entire operation to occur without requiring any complex index-tracking cognitive load.

Divide and Concat

Jorg has provided a mathematically accurate and highly precise solution that demonstrates command of Perl's multidimensional array manipulation and list processing capabilities. The solution has been designed with a heavy emphasis on reducing iteration overhead, and uses a clean and logical approach to conditional checking. Overall, the implementation is an efficient way to manage data structures for all of the tasks required to complete this project.

Perl Weekly Challenge 373

W. Luis Mochan gives an interesting, very mathematical view of the difficulties and has elevated the difficulty of the tasks by discussing the different ways each of these tasks can be solved through their mathematical representations. The way the solution uses Perl Data Language is unique in its creativity and clearly shows how matrix operations and vector operations can be applied in a different manner to solve an algorithmic process much more efficiently and faster than typical procedural methods. This is a remarkable, challenging read, demonstrating the way that thinking in terms of vectors alone can change the way standard procedure of manipulating data can be made into a high level, abstract manner.

Because your list, your list I can’t resist

Packy offers a unique perspective on the challenge by framing the approach through an interesting musical context, followed by a really clean, multilingual show-off with a few different language options. As a polyglot expert, Packy's write-up shows a number of idiomatic and clean ways to solve problems in both Perl and Elixir. The solutions have been complimented for their clear structure, readable transformations of data, and the highly contrasting ways in which they use the procedural power of Perl with the functional, pipeline-based elegance of Elixir.

The week of lists

This paragraph describes the outstanding quality of Peter's work in executing his weekly assignments and projects using clear and detailed methods. He concentrates on providing clear and easy to understand explanations of all aspects of the problem using very pragmatic solutions with less complex algorithms than would be required to complete this task, and thus have produced solutions with low run times and high readability. Another benefit of using this strategy is that it will have produced many examples of good clean and maintainable code, as well as simple Perl code showing how to accomplish structural validation without additional runtime cost.

The Weekly Challenge - 373: Equal List

The analysis that Reinier provided on this challenge is truly impressive due to the systematic approach used to cover edges and validate input. The solution makes a great balance between how computer efficient it is to run while at the same time being easy to scan through for code due to well-named variables and clearly defined logical conditions. This is a great resource for developers looking to implement defensive programming and build highly maintainable systems.

The Weekly Challenge - 373: List Division

Reinier has presented a very clear and logical way to solve the list partitioning problem through clarity in procedural programming and appropriately managing data through effective use of algorithms. The implemented solution is easy to follow, with simple looping structures and clearly defined conditions used to divide the collection according to specification without introducing complexity into the underlying architecture. This solution is a perfect example of pragmatic programming, where simplicity, maintainability, and consistency take precedence over unnecessary abstraction.

The Weekly Challenge #373

The analysis provided by Robbie consists of an analysis of the weekly problems and an an idea of what you'd have to do. The breakdown of the problems will be thoroughly examined and will include thorough analysis of all the constraints on the solution as well as a commitment to validate input sufficiently to account for any and all edge cases and to deal with them accordingly. The combination of cleanly structured idiomatic programming style (including the use of loops) with clear and explicit comments that explain the logic behind the programming additions and modifications, make this a great reference source for new and experienced programmers to use.

There Is No Equality Without Division

Roger performs a beautiful and tidy example of modern solutions to solving problems through example in different programming languages and paradigms. The two different types of tasks, structural validation and partitioning, have been broken down into separate clear logical blocks that allow for high readability of solutions and the use of commonly used data structures without the use of complex loops. The write-up contains an excellent comparison of the different language features that reduce index-tracking overhead while still providing optimal run-time efficiency and successfully illustrates how functional programming techniques can be used successfully with non-functional programming techniques.

Joining and splitting lists

Simon has presented an impressively logical and practical polyglot demonstration that compares the elegant way of handling the first task in Python to how it is done through direct translations into Perl. The first task's solution is particularly notable for its concise efficiency and consists of a great, simply written one-liner using native methods to join strings and performing a direct comparison to form the structure of the list being checked. In the second task, Simon has shown a brilliant method for diving an array into equal components by taking advantage of the mathematical operation called divmod or remainder and relying on destructive splice operations to divide the arrays evenly without creating any overhead from having to manage cumbersome index numbers.